The Aircraft Engine Component Test Stand/Peculiar Support Equipment (AECTS/PSE) is a specially designed Intermediate Level (I-Level) instrument for testing Generator Converter Units (GCU's) used in the F/A-18 A-D and F/A-18 E/F. It is designed to test GCU systems as a whole without removing components. Because all GCU components remain connected during an AECTS/PSE test, and there are a limited number of test points, it can be difficult to pinpoint and correctly diagnose the source of a failure. GCU's that fail an AECTS/PSE test thus require laborious disassembly and component-by-component testing to determine which components may be defective. With 36 silicon controlled rectifier (SCR) channels on the F/A-18 A-D GCU and 54 on the F/A-18 E/F GCU, complete testing of all of the SCR modules in a GCU is very time consuming. Thus, there is a compelling need for a solid functional test apparatus that enables rapid and reliable testing of SCR modules for both F/A-18 A-D and F/A-18 E/F GCU's.